Vitamin D deficiency linked to daytime sleepiness

A new study finds a correlation between the 'sunshine vitamin' and daytime fatigue.

For anyone who has suffered through the achy slog of sleepiness during the day, the dream of a quick pick-me-up is all too familiar. Naps are generally unrealistic for the post-preschool set and an afternoon coffee never really quite cuts through the fog. But what if the solution was as simple as taking vitamins and getting some sunlight?

According to research presented at the 25th annual meeting of the Associated Professional Sleep Societies, patients with daytime sleepiness and musculoskeletal pain are likely to have vitamin D insufficiency or deficiency.

"Clinicians should be alerted to the fact that patients with [sleep disturbance and] pain may have a potentially reversible mechanism for musculoskeletal discomfort," said Dr. David E. McCarty, sleep medicine specialist at Louisiana State University Health Sciences Center at Shreveport. "Testing for vitamin D deficiency should be considered, even in areas with high amounts of natural sunlight exposure."

Vitamin D is found in dietary sources like fish, eggs, fortified milk,and cod liver oil; in addition, the sun contributes significantly to the daily production of vitamin D in the body.

The researchers reported that in general, many patients with vitamin D deficiency also experience diffuse musculoskeletal pain, known as osteomalacic myopathy, which can often sabotage a good night’s sleep. Fortunately, it responds well to supplemental vitamin D treatment.

With this in mind, the team decided to test the vitamin D levels of patients who had complained of chronic pain as part of the workup that was done for other sleep disturbances. McCarty and colleagues performed research and reviews of 153 patients at a sleep clinic. Eighty-four percent of patients had either vitamin D insufficiency (30 percent) or deficiency (54 percent).

They discovered that some patients who exhibited low levels of vitamin D experienced complete resolution of daytime sleepiness symptoms after treatment for vitamin D deficiency. McCarty and colleagues concluded that it is biologically plausible that low vitamin D could contribute to sleepiness because of its role in systemic inflammation.

Noted McCarty, "More research is needed to define whether vitamin D deficiency mechanistically contributes to excessive daytime sleepiness and to determine if supplementation offers a novel method for alleviating it."